PC Hardware in a Nutshell, 3rd Edition

Real-World Power Supplies Compared

Table 26-18 lists the output by voltage of three nominally 350-watt ATX12V power supplies. The PC Power & Cooling Turbo Cool 350 ATX/ATX12V is a premium unit, with a street price of about $65; the Antec SL350 is a name-brand unit that sells for about $45; the Sparkle Power Inc. (SPI) FSP350-60BN is another name-brand unit that sells for about $50. We would like also to have compared a no-name Pacific Rim power supply, but finding technical specifications for such units is impossible, probably because they vary so much from one lot to another that no one bothers to test them.

The three key voltage rails are +3.3V, +5V, and +12V. Note that, although all the power supplies list individual maximum outputs for +3.3V and +5V, they also note maximum combined output of +3.3V and +5V—215W for the PC Power & Cooling unit, 230W for the Antec, and 220W for the SPI unit. Antec is alone, however, in specifying maximum combined output on the +3.3V, +5V, and +12V rails.

Table 26-18. Output comparison of three nominal 350 watt power supplies

	PC Power & Cooling Turbo-Cool 350 ATX			Antec SL350			Sparkle Power Inc. FSP350-60BN
Rail	+/-	Amax	Watts	+/-	Amax	Watts	+/-	Amax	Watts
+3.3VDC	1%	28	92.4	5%	28	92.4	4%	28	92.4
+5VDC	5%	32	160	5%	35	175	5%	32	160
Maximum combined Wattage: 3.3 + 5			215			230			220
+12VDC	5%	15	180	5%	16	192	5%	15	180
Maximum combined Wattage: 3.3 + 5 + 12			n/a			330			n/a
-5VDC	5%